# webpack-dev-middleware vulnerable to Path Traversal via non-slash-terminated publicPath

Advisory record · `GHSA-g84c-rxfj-3j2c`

- **Identifiers:** `GHSA-g84c-rxfj-3j2c` · `CVE-2026-76844`
- **State:** Confirmed
- **Severity:** CVSS 8.3 High
- **Critical:** No
- **Weakness (CWE):** [CWE-22](https://cwe.mitre.org/data/definitions/22.html) · [CWE-787](https://cwe.mitre.org/data/definitions/787.html)
- **Tags:** [Path traversal](https://agentprime.io/advisories/tag/path-traversal.md) · [Memory corruption](https://agentprime.io/advisories/tag/memory-corruption.md)
- **Published:** 29 Sept 2026
- **Updated:** 3 Oct 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 29 Sept 2026, 16:59 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `webpack-dev-middleware` (npm): affected `>=8.0.0, <8.3.0 || <7.4.6`; fixed in `8.3.0`, `7.4.6`

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 8.3 High, CVSS 4.0: `CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N`, from CNA (VulnCheck)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0059, the 48th percentile, on 10 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 31 Oct 2026, 13:34 UTC: First seen by agentprime
- 31 Oct 2026, 13:34 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-g84c-rxfj-3j2c)

## Sources

- [GitHub Advisory Database: GHSA-g84c-rxfj-3j2c](https://github.com/advisories/GHSA-g84c-rxfj-3j2c)
- [OSV: GHSA-g84c-rxfj-3j2c](https://osv.dev/vulnerability/GHSA-g84c-rxfj-3j2c)
- <https://github.com/webpack/webpack-dev-middleware/security/advisories/GHSA-g84c-rxfj-3j2c>
- <https://nvd.nist.gov/vuln/detail/CVE-2026-76844>
- <https://github.com/webpack/webpack-dev-middleware/pull/2404>
- <https://github.com/webpack/webpack-dev-middleware/commit/13344e78b26d88fe9b7c8381a3860e248a52359b>
- <https://github.com/webpack/webpack-dev-middleware/commit/cefccbac330c29052fc6dffe85fd292ea2ac782b>
- <https://github.com/advisories/GHSA-wr3j-pwj9-hqq6>
- <https://github.com/webpack/webpack-dev-middleware>
- <https://github.com/webpack/webpack-dev-middleware/blob/v8.1.1/src/middleware.js>
- <https://github.com/webpack/webpack-dev-middleware/releases/tag/v7.4.6>
- <https://github.com/webpack/webpack-dev-middleware/releases/tag/v8.3.0>
- <https://www.vulncheck.com/advisories/webpack-dev-middleware-path-traversal-via-offset-slice-on-a-non-slash-terminated-publicpath>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-g84c-rxfj-3j2c>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

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The web page: <https://agentprime.io/advisories/GHSA-g84c-rxfj-3j2c/>. Everything for agents: <https://agentprime.io/llms.txt>.